北京自由电子激光最近进展──实现饱和振荡

Recent Progress of the Beijing FEL──Realized Saturated Oscillation

北京自由电子激光（ＢＦＥＬ）装置于１９９３年底在１０．６８μｍ处实现了饱和振荡．输出激光能量为３ｍＪ，饱和平顶宽度２μｓ．对应饱和振荡平均功率为２１０ｋＷ（宏脉冲），峰值功率约为２０ＭＷ，比自发辐射高８个量级，单程小讯号净增益为２４％，转换效率为０．４５％，与理论预期结果相符．光束质量接近衍射极限．目前装置可工作于９－１１μｍ．

Beijing FEL facility has been built in IHEP,the saturated oscillation has been obtained at a wavelength of 10.68μm,on Dec.28,1993.The average output energy and the pulse width were measured respectively to be 3mJ,2μs.The corresponding osillation power is greater than 210kW,peak power is about 20MW, which is about 108 times higher than that of spontaneous emission. The FWHM of the FEL spectracal bandwidth is less than 2%.The small signal net gain is 24% per pass.The extraction efficiency is 0.45%.In the present experimental resules,BFEL can be saturated by changing electron energy at the wavelength range from 9-10μm,the maxmium average output energy and extraction efficiency are 10mJ,0.52% respectively,the minimum spectral bandwidth of 0.3% has achieved by shorting cavity length.